Trains travelling in both directions – and carrying some 220 passengers- struck at least a dozen horses near Waterbeach, it was confirmed tonight.

The incident happened just before 5.15pm last night on the Fen Road crossing at Milton, between Waterbeach and Cambridge.

British Transport Police has spent the day investigating how the collision happened.

Sergeant David Barker said: “We are very keen to find out who the horses belong to. “At the moment it is not clear how many horses died in the incident, however, we now believe that at least 12 were killed.

“I also want to know how the horses came to be on the tracks. If anyone has any information, which they think that could help us in our investigations please get in touch.”

The breeds of the horses, which are believed to have come from the fields in the Fen Road area, are unknown. Officers are keeping an open mind into the cause of the incident.

Cambridgeshire Constabulary, the ambulance service and fire service also attended the incident. A female passenger was taken to hospital with minor injuries and later discharged.

Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference ESUB/B2 of 20/11/14.

Information can also be passed anonymously to independent charity Crimestoppers on 0800 555 111

One passenger was taken to Addenbrooke’s Hospital with minor injuries in the aftermath of the incident while East of England Ambulance crews assisted with other minor injuries at the scene.

The trains involved were the Cross Country service from Cambridge to Birmingham, and another from Birmingham to Stansted Airport.

A spokesman for the East of England Ambulance Service said: “We assessed four patients at the scene, three of which were checked over but did not need further treatment.

“A fourth female patient was assessed and taken to Addenbrooke’s Hospital as a precaution after suffering what appears to be minor head injuries.”

Firefighters from Cambridge, Cottenham and Ely were also called to the incident.

Crews arrived to find a train made up of three carriages had collided with a number of horses at the rail crossing on Fen Road in Milton. There were around 220 passengers on the train.

Station commander, Paul Clarke said: “The crews opened the doors of the carriages to allow fresh air to circulate and distributed water to the passengers on board.”

Firefighters remained at the scene until the train was successfully repaired and moved to the nearest train station.